Projects: UDL : UDL Electricity Balloons and charges(3-4)

LEARNING GOAL:
Electricity is based on electric charges.
There are two kinds of charges: positive

and negative

.
Positive and negative charges together cancel each other out.
Opposite charges attract (pull together). (positive and negative attract.)
Like charges repel (push apart). Positive and positive repel. Negative and negative repel.

How can you make electricity?
Cannot resolve external resource into attachment.
(from big box of art)
Put electric charge on balloons and see what they do.

Engage

Electric charges are everywhere. They are very small - even smaller than atoms! - so you can't see them. There are two kinds of electric charge, called positive

and negative

Every object has a HUGE number of both kinds of charge. If the number of positive and negative charges is equal, they cancel each other out and the object is electrically neutral. But the object can have more positive than negative charges, or more negative than positive charges. Then it becomes either positively charged or negatively charged.

You can't create electric charges out of nothing. But when you rub a balloon on wool, positive charges collect on the balloon and negative charges collect on the wool. Then you can observe the force between them.

Draw a balloon and a wool sweater. Using the Stamp tool, put 10

signs and 10

signs on the balloon. Also put 10

signs and 10

signs on the wool sweater.

DRAWING TOOL - with

and

stamps available. what size is best?

help with using the stamp tool.

Now drag some

charges from the wool to the balloon. This is what happens when you rub them together.

Materials

Explore

Blow up two balloons, tie them shut, and tie on a piece of string about 50 cm long.

Should they bother with this?
Draw 15 plus signs on the red construction paper and cut them out.
IMAGE

Draw 15 minus signs on the black construction paper and cut them out.
IMAGE

Stick 5 plus signs and 5 minus signs on each balloon, near the opening.
IMAGE

Stick 5 plus signs and 5 minus signs on the wool sweater.
IMAGE

Rub each balloon on the wool sweater. Rub all sides of the balloon, not just one side.
IMAGE

Explain

When you rub a balloon on wool, some negative charges move from the wool to the balloon. Circle the right words to make these statements true.

The wool becomes (negatively / positively) charged.
One balloon becomes (negatively / positively) charged.
The other ballon becomes (negatively / positively) charged.

Include?? or use drawing tool instead?
To show this, move a paper minus sign from the wool to each balloon. Also move a paper plus sign from each balloon to the wool.
Count the plus and minus signs on the balloons and the wool. Which has extra plus signs and which has extra minus signs? Which is positively charged and which is negatively charged?
ANSWER BOX

Positive charges attract (pull toward) each other.
T F
Positive charges repel (push away from) each other.
T F
Positive charges attract negative charges.
T F
Positive charges repel negative charges.
T F

Elaborate

Stick a piece of tape about 10 cm long to a table. Hold one end and quickly rip the tape from the table. This will move some extra charges to the tape – just like rubbing the wool and the balloon together.

Evaluate

Rub a balloon on your hair, and then hold the balloon near your head. What happens? Why?
ANSWER BOX

an alternative version:
Here is a picture of a balloon that a girl has rubbed on her hair. Put and stamps where there are extra positive or negative charges.

DRAWING TOOL with a picture and stamps

You have probably noticed that sometimes, after you walk across a carpet or get out of your car, you make a spark when you touch something with your finger. Explain what you think causes the spark.
ANSWER BOX